Death of a Gardener - Molly Masters Mysteries, #3

Gardening is not usually considered a blood sport, but whenever cartoonist Molly Masters is out in the yard she must contend with the harassing comments of her neighbor, Helen Raleigh, who once owned Molly's house. Then, after a particularly unpleasant confrontation, Helen is shot dead on Molly's property--and a shocking secret is revealed. When Molly shoves her trowel into the dirt of the murder investigation, she starts receiving threats--and realizes that one determined killer could quiet her questions forever.